A number of fastening or clamping devices have been devised for a variety of purposes. In one application, clamps are used with electrical systems for the purpose of connecting electric shielding or insulation about electric wires. In particular, such clamps connect the shield to an electrical connector that typically receives current carrying conductors. In U.S. Pat. No. 4,646,393 to Young, issued Mar. 3, 1987 and entitled "Clamping Band for Electromagnetic Shielding Band Cable Connector," a clamping device is disclosed for use in constraining electromagnetic shielding. The device is a one-piece cable tie in which a buckle is formed at one end of the band. The buckle includes a pair of abutting wings that are welded together after folding thereby creating a single, longitudinally extending opening. The free end of the band can be inserted through the buckle opening a number of times to provide a number of band revolutions or spirals.
A commercially available cable tie made by the assignee of the present invention includes a buckle having a raised section with slots formed on opposing sides of the raised section. The raised section is formed by punching the buckle in two opposing directions. The buckle side edges are flat and not raised. The band of the cable tie is inserted through the two buckle slots during each wrap of the band about the object to be held or constrained. This type of cable tie has also been made as one-piece.
Other representative one-piece clamps are illustrated in U.S. Pat. No. 356,083 to Schrader, et al., issued Jan. 11, 1887 and entitled "Clamp For Hose Couplings" and U.S. Pat. No. 157,032 to Smith, issued Nov. 17, 1874 and entitled "Bail-Ties". In the Schrader, et al. patent, a hose clamp is described having a number of projections that can be folded to provide a buckle or catch-like configuration. In the Smith patent, wings integrally formed with the band are bent over to engage portions of the band. A one-piece cable tie is also described in U.S. Pat. No. 3,660,869 to Caveney, et al., issued May 9, 1972 and entitled "One-Piece Cable Tie". This cable tie is characterized by the use of a row of teeth disposed on one longitudinal surface of the strap. The patent also describes a molding process for making the cable ties. One-piece cable ties similar to that disclosed in Caveney, et al., are described in U.S. Pat. No. 4,272,870 to McCormick, issued Jun. 16, 1981 and entitled "Synthetic Plastics Tie Member" and U.S. Pat. No. 4,507,828 to Furutsu, issued Apr. 2, 1985 and entitled "Bundling Belt Device". The cable ties of McCormick and Furutsu are both characterized by the use of serrated teeth disposed on one longitudinal surface of the band. Attachment of the band to buckle in the McCormick patent is achieved by engagement of the serrated teeth with complementary teeth disposed on the interior of the upper surface of the buckle. In contrast, attachment of the band to the buckle in the Furutsu invention is accomplished by engagement of the serrated teeth with a single, ratchet-like tooth disposed on the interior of the lower surface of the buckle.
Multi-piece clamps are illustrated in U.S. Pat. No. 2,455,760 to Gustafson, issued Jan. 20, 1943 and entitled "Hose Clamp" and U.S. Pat. No. 4,262,406 to Fredrickson et al., issued April 21, 1981 and entitled "Method of Assembling Strapping". The Gustafson invention is characterized by one or more clips under which, or through which, a separate metallic strap is disposed. The invention of Fredrickson et al. includes a strap fastener having a plurality of slots for receiving a separate, flexible strap. A two-piece cable tie is also described in U.S. Pat. No. 4,222,155 to Oetiker, issued Sept. 16, 1980 and entitled "Hose Clamp". The invention of Oetiker includes a band having at least one tapered end for engaging the other end of the band in a continuously smooth, stepless fashion to reduce any gap existing between the band and object encircled. A separate bridge member is utilized to constrain or hold the two ends of the band in place.
Although one-piece clamps or cable ties are known and have been used in connection with electric cable or the like, it remains desirable to provide a one-piece cable tie that provides improved tightness whereby any gap that might result between the object and the band is reduced even for very small diameter objects, can be made relatively inexpensively without waste of material and can be readily fastened to a hose or cable. Further, it remains desirable to provide a one-piece cable tie that exhibits improved engagement characteristics between the band and the buckle. More specifically, there exists a need for a one-piece cable tie that promotes engagement of band to the buckle by reducing the friction existing therebetween. In that regard, the present invention is directed to a one-piece clamp for meeting such major objectives.